The present invention relates generally to the field of devices designed to prevent the unauthorized use of electrically powered devices and, more particularly, to a locking device which engages both prongs of an electrical plug and prevents such prongs from being inserted into an electrical outlet.
For personal and/or safety reasons, it is often desirable to prohibit the use of certain electrically operated devices. For example, with potentially dangerous power tools and/or other electrical appliances such as electric table saws, electric hand saws, power drills, toasters, irons and so forth, it is desirable to prevent children or other unauthorized individuals from using such tools and/or appliances so as to avoid potential injury to the user, potential property damage, and/or potential fire hazard. Various types of locks and other mechanisms for use with electrically powered devices, electrical appliances and other equipment for preventing unauthorized use a re well known in the art. Such locking devices are also widely used by parents to restrict use of certain types of equipment such as televisions, radios, computers, VCRs, stereos, electronic games and so forth.
Many of the prior art safety/locking type plug devices are complex to use and expensive to manufacture. For example, some devices render the entire plug inaccessible by placing the plug within a locked enclosure. See, for example, U.S. Pat. Nos. 4,488,764; 4,666,224; 4,673,230; and 6,159,025. Other devices operate by securing or clamping a lock to the prongs of the plug using various locking mechanisms. See, for example, U.S. Pat. Nos. 5,666,829 and 5,795,166. Still other devices utilize the insertion of pins, or the shackle of a padlock through the holes in the prongs of a plug, to complete attachment of the locking mechanism. See, for example, U.S. Pat. Nos. 4,563,048; 4,566,279; and 5,848,905. Although some of these locking devices utilize the holes in the prongs of a plug to secure the locking mechanism, many of these devices can be maneuvered and manipulated such that at least a portion of one or both prongs can be inserted into and can make electrical contact with an electrical outlet which can result in an electrical shock or other injury or damage to the user and/or the electrical devices. Still further, other locking devices utilize spring loaded pin members, and some locking devices attach through one of the holes in a prong of a plug, which arrangement can likewise result in an electrical shock if the free prong is inserted into an electrical outlet.
It is therefore desirable to provide a relatively simple and easy to operate locking device which not only prevents unauthorized use of a particular electrical appliance or other electrically powered device, but also prevents inadvertent or partial contact with an electrical outlet when the locking device is properly installed.
Accordingly, the present invention is directed to overcoming one or more of the problems set forth above.